Sustainable energy systems are complex sociotechnical systems with a social network of many players that “together” develop, operate, and maintain the technical infrastructure. No single player controls the system, but their actions are coordinated through a range of institutions—informal and formal rules—and regulations. As the control is distributed among actors, the overall system behaviour (at different time scales) emerges from operating practices and characteristics, from (dis)investment decisions, and from other aspects of the players’ strategies.

Sustainable energy systems require a complex, irreducible approach for design and operation and for robust what-if analyses. Essential aspects of the overall system behaviour or structure might be misunderstood or even overlooked if traditional methods continue to be applied; that is, methods which examine the connections between the heterogeneous parts and the whole system of systems are needed.

The purpose of this special issue is to publish high-quality research papers as well as review articles addressing recent advances on complexity in relation to energy systems. Original, high-quality contributions that are not yet published or that are not currently under review by other journals or peer-reviewed conferences are sought.

Potential topics include but are not limited to the following:

• Agent based modelling and simulation
• Applications of network science concepts to energy problems
• Energy and social theory/social practice
• Energy consumption and behaviour
• Energy security, affordability, and poverty
• Sustainable economic growth in energy systems
• Energy and the environment
• Energy transition
• Coevolution within the energy vectors and with other sectors such as transport
• Path dependency and inertia
• Energy services and business models
• Disruptive energy technologies
• Energy policy and regulation